1. Field of the Invention
The present invention relates in general to sports training devices and in particular to ball pitching machines for practicing baseball and softball batting and fielding skills as well as other sports play involving interaction with pitched balls.
2. Prior Art
The present invention was conceived and developed after the inventor searched to locate and purchase a ball pitching machine suitable for training his 12 year old son for Little League Baseball play. A manually operated pitching device for plastic "polyballs" was located and purchased. This device pitches low weight hollow plastic balls by a spring powered slinging mechanism and proved to be less than desirable for the purpose required because the machine could not effectively pitch the balls over the Little League regulation distance from the pitching mound to home plate, 46 feet, and because the low weight hollow plastic balls de-accelerate in velocity during flight through air much more rapidly than do actual baseballs. The "polyball" pitching machine simply did not produce the desired training for the inventor's son because it did not duplicate the pitching and flight of baseballs as encountered in actual Little League play. Rotating wheel pitching machines were considered, but rejected because of cost and safety considerations along with concerns over the need for an electrical power source at the practice field. The inventor desired and could not locate a manually actuated pitching machine which would deliver soft safety balls of the weight and size of an official Little League Baseball over the fill official distance from the pitching mound across home plate at the velocities and trajectories expected in actual play. An impact pitching mechanism was developed and reduced to practice for this purpose. The device proved to be very fictional and effective as a training aid and has been refined into the invention described here. No other device is known which provides similar service as cost effectively, safely, or conveniently as the present invention.
A number of the presently available ball pitching machines for baseball and softball batting practice employ motorized spinning wheels to throw baseballs and softballs. These spinning wheel machines are very effective, but are quite bulky and expensive compared to the present invention and all require electrical power at the location of operation. The base model of the present invention is manually operated. An optional electric motor powered actuator may be employed with the present invention to allow an athlete to work independently. This feature of the present invention does not require an onsite electrical power outlet because high energy efficiency allows utilization of a battery powered motor for actuation.
Spinning wheel pitching machines transfer kinetic energy to the ball being thrown by griping the ball between two rotating wheels or between a single rotating wheel and a stationary plate. The ball is slung from the spinning wheel apparatus with velocity and spin. The spinning wheel type pitching machines very effectively throw any type of ball including actual hard game balls. The present invention employs impact to transfer kinetic energy into balls being pitched. Only soft resilient practice balls are effectively pitched by the present invention. The inventor considers this limitation to be a positive feature in that user safety is enhanced by the present invention's inability to pitch hard balls which are more likely to cause injury to anyone who might be accidentally struck than are soft resilient practice balls. The present invention is substantially different from all spinning wheel type ball pitching machines by virtue of employing an impact means to pitch a ball instead of the "grab and sling" means employed by rotating wheel ball pitching machines.
Another mechanical ball pitching machine type employs a rotatable pitching lever. The ball being pitched receives kinetic energy from the pitching lever by being pushed around a circular track or griped in a holding device at the outer end of the lever as the lever rotation is rapidly accelerated by force from some type of mechanism, typically a spring device. The ball being pitched is slung from the device when either the slinging lever strikes a mechanical stop or the ball holding device mechanically releases the ball.
The "Spring Type Ball Throwing Machine" of Glover et al U.S. Pat. No. 4,220,130; the "Mechanical Baseball Pitching Machine" of Ponza U.S. Pat. No. 2,792,822; the "Toy Cannon" of Nichols U.S. Pat. No. 1,352,681; the "Mechanical Base Ball Pitcher" of Long U.S. Pat. No. 1,190,565; and the "Catapult For Throwing Projectiles" of McGlashan U.S. Pat. No. 629,044 are all rotating lever slinging type pitching machines. Rotating lever ball slinging pitching machines accelerate both the ball being pitched and the pitching lever simultaneously to pitch the ball. Once the ball is pitched the lever and attached rotating apparatus retain all the kinetic energy that they had before the ball was pitched or lose their energy into the surrounding apparatus and environment by striking a stop. The energy required to pitch a ball by a slinging type pitching machine thus equals the sum of the energy required to accelerate the lever and associated rotating apparatus plus the energy required to accelerate the ball. In an impact type ball pitching machine a striker lever is first accelerated alone. The accelerated lever then strikes a stationary ball and transfers a portion of its kinetic energy into the ball to produce the pitch. The striker lever and associated pitching apparatus of an impact pitching machine can be significantly de-energized upon pitching the ball. If the energy transfer from the striker apparatus into the ball is carried out with high efficiency, as is the case when soft resilient balls are utilized with the present invention, the total amount of energy required to effect a pitch is just slightly greater than the actual kinetic energy carried by the pitched ball. An impact pitching machine can thus be much more energy efficient than a slinging type pitching machine and require significantly less actuation energy and smaller machine components to produce a given pitch.
The present invention differs substantially from all lever slinging type ball pitching machines. Though bearing some resemblance in appearance to these devices, the present invention employs a totally different means to impart kinetic energy into a ball to effect the pitching of that ball. The present invention is more specialized than are the lever slinging type ball pitching machines and by design only works effectively with soft resilient balls. Slinging type pitching machines may be utilized with hard game balls, hollow low weight "polyballs", or the same soft resilient balls employed by the present invention. Slinging type pitching machines do not pitch with the high energy efficiency that the present invention achieves with soft resilient balls and thus require greater actuation energy and a larger apparatus to pitch balls of similar weight with speeds equivalent to that achieved by the present invention.
A number of impact pitching machines have been invented in the past. The "Ball Projectile Machine" of Ridley et al U.S. Pat. No. 4,721,091; the "Spring Type Ball Projecting Device" of Young et al U.S. Pat. No. 4,185,608; the "Portable Ball Throwing Machine With One-Way Clutch" of Haller U.S. Pat. No. 4,237,851; the "Spring Type Apparatus For Projecting Balls" of Andersson U.S. Pat. No. 4,345,577; the "Spring Type Ball Projecting Device" of McGill U.S. Pat. No. 3,841,294; the "Spring Type Projecting Device" of Scott U.S. Pat. No. 3,779,227; the "Projecting Device" of Binks U.S. Pat. No. 2,660,158; the "Ball Projector" of Binks U.S. Pat. No. 2,660,157; the "Toy Machine Gun" of Miller U.S. Pat. No. 1,916,680; the "Ball Throwing Device" of LACOSTE U.S. Pat. No. 1,916,680; the "Missile Projection Device" of Kahler et al U.S. Pat. No. 1,809,708; the "Ball Throwing Device" of LACOSTE U.S. Pat. No. 1,777,976; and the "Toy Machine Gun" of Brown U.S. Pat. No. 1,480,499 all utilize impact by a spring driven striker as the means by which kinetic energy is transferred into projectiles which are then ejected singularly from the device. The present invention utilizes a rotating crankshaft mechanism to store energy by stretching linear tension springs attached to the cranks then rapidly releases that energy into a striker lever and hammer rigidly attached to the crankshaft as the crankshaft rotates over-center allowing the springs to contract and accelerate the rate of rotation. Of the prior art impact ball pitching machines only the "Ball Projectile Machine" of Ridley et al U.S. Pat. No. 4,721,091; the "Spring Type Ball Projecting Device" of Young et al U.S. Pat. No. 4,185,608; and the "Portable Ball Throwing Machine With One-Way Clutch" of Haller U.S. Pat. No. 4,237,851 utilize a rotating crankshaft type mechanism to store energy by stretching a spring then rapidly release that energy into a striker as the crankshaft rotates over-center. The other prior art impact ball pitching machines employ a striker cocking and release action. In some of these devices the striker is pulled or pushed in one direction against a spring then released to recoil in the opposite direction and strike the ball being pitched. In other of these devices the springs are stretched while the striker is held fast then released allowing the spring to rapidly force the striker in the direction required to impact the ball. The present invention is substantially different from all of these non-crankshaft actuated impact pitching devices by virtue of employing a rotating crankshaft mechanism which rotates in one direction carrying the rigidly attached striker lever and hammer.
In the case of the "Spring Type Projecting Device" of Scott U.S. Pat. No. 3,779,227 the striker is a leaf spring which rotates in one direction about an axis and is cocked by engaging a stop at the outer perimeter. The leaf spring of Scott's device flexes as the shaft rotation continues with the outer perimeter of the striker stopped. When the stop is released the flexed leaf spring of Scott's device rapidly straightens and strikes a ball positioned in a holder. The present invention differs substantially from the "Spring Type Projecting Device" of Scott by virtue of the present invention utilizing a crankshaft mechanism and linear coil tension springs instead of a rotating flexing leaf spring striker as employed with Scott's invention.
In each of the three prior art impact type pitching machines which employ a crankshaft mechanism a single friction reducing bushing supports a rotation shaft rigidly attached to one side of a striker. Additionally, in each a single linear tension spring is attached to a pin extending from the side of the striker opposite the side to which the rotation shaft is attached and off-set from the center of the rotation shaft to form a crank. In the case of the "Ball Projectile Machine" of Ridley et al U.S. Pat. No. 4,721,091 the spring attachment pin is located on the striker toward the end of the striker which actually strikes the ball to effect a pitch. In the case of the "Spring Type Ball Projecting Device" of Young et al U.S. Pat. No. 4,185,608 the spring is attached at a location 90 degrees behind the center line of the ball striker. In the case of the "Portable Ball Throwing Machine With One-Way Clutch" of Haller U.S. Pat. No. 4,237,851 the spring is attached on the opposite side of the rotation shaft 180 degrees from the direction in which the striker extends. These differences in spring attachment location relative to the direction in which the striker extends from the rotation shaft are the fundamental differences between these three prior art crankshaft actuated impact ball pitching machines. In the preferred embodiment of the present invention the striker lever extends from the crankshaft in the direction 180 degrees from the direction in which the cranks extend, similar to the arrangement employed in Haller's invention. The present invention is substantially different from the impact type ball pitching inventions of Ridley et al and Young et al on this basis as well as others discussed below.
There are sound reasons for attaching the linear springs to the opposite side of the rotation shaft from the direction in which the striker extends. In the case of the present invention this arrangement allows the ball feeding and holding mechanism to be situated on the opposite side of the striker rotation shaft from the side to which the springs are attached to the enclosure. Components of the pitching mechanism of the present invention are more evenly distributed about the enclosure by this arrangement allowing ease of fabrication and access as well as generally better functionality than would be enjoyed by another arrangement. Additionally and more significantly, by attaching the springs to the crankshaft on the side 180 degrees from the direction in which the striker extends from the crankshaft results in enhanced mass and force balance about the crankshaft axis of rotation which results in improved performance of the pitching mechanism and enhanced durability of the friction reducing support bearings of the crankshaft of the present invention.
Though the present invention attaches the linear springs to the crankshaft of the ball pitching mechanism in the direction 180 degrees from the direction in which the striker extends as does Haller, the present invention differs fundamentally and substantially from Haller's invention as well as Ridley's et al and Young's et al in other areas. To avoid bending and twisting effects on the crankshaft of the present invention, structural symmetry is employed. The striker of the present invention is rigidly attached to the center of the crankshaft directly between two friction reducing bearings which support the crankshaft. Additionally, two linear tension springs are attached to the crankshaft of the present invention at locations evenly spaced and on either side of the striker. For balance, these two linear tension springs are of similar size and characteristic. For improved efficiency and durability the present invention employs friction reducing bearings to attach the linear tension springs to the crankshaft cranks. Additionally, the one-way clutch mechanism of the present invention is an integral part of the striker lever and thus is also situated symmetrically in the mechanism. A clutch pad composed of a resilient material strip is attached to a portion of the inside surface of the enclosure of the present invention along and slightly outside the arc scribed by the outer edge of the striker hammer. A pawl attached to the outer edge of the striker hammer allows the striker lever and hammer to move freely past the resilient clutch pad strip in the direction required to effect a ball pitch. When external actuation force is removed from the crankshaft before the crankshaft rotates over-center the pawl engages the resilient clutch pad strip and stops the crankshaft and attached mechanism from rotating in the opposite direction due to the pull of the springs. The present invention differs substantially and beneficially from all prior art rotating crankshaft linear spring driven impact ball pitching devices by virtue of employing a unique and improved striker lever and hammer mechanism, symmetrically located balanced twin springs, and twin support friction reducing bearing as well as a unique and improved one-way clutch mechanism. All loads and supports other than the actuation lever are symmetrically located with respect to the ball striking mechanism of the present invention. Additionally, the strikers on the three prior art ball pitching machines which employ rotating crankshaft mechanisms are short, blunt, and stiff compared to the present invention. These strikers do not flex and recoil upon impact with the balls being pitched as does the striker of the present invention. The present invention utilizes a relatively long and slender striker lever which by design does flex and recoil slightly during the impact with the ball being pitched. The flex and recoil action of the striker lever of the present invention contributes to the efficiency with which energy is transferred from the pitching mechanism into the ball being pitched by allowing longer contact time between the striker and ball during impact. The time of contact between the striker and ball during impact coupled with the force applied during that period of contact contribute to the energy transfer efficiency from the striker into the ball. The longer the time of contact and the greater the force exerted during that contact then the greater the amount of energy that is transferred. The present invention additionally differs substantially from the three prior art impact ball pitching devices which employ a rotating crankshaft on the basis of utilizing a relatively long slender striker lever which by design flexes and recoils during impact with a ball to enhance the efficiency with which energy is transferred from the striker into the ball.